I was sole developer on that project.

But here's a thought for you: you can only achieve mediocrity if all choices require 100% buy-in from all interested parties.

> I have found most people simply don't care and don't want to learn it.

No one likes to have their cheese moved. But cheese moves nevertheless.

> We did functions 30 years ago.

Most people saying that probably don't realize that what computer programmers call "functions" are not what mathematicians call "functions."

The reason FP is becoming popular now is that the distinction now matters much more than ever in today's multicore world, where multiprocessing is often the only practical way to make software substantially faster.